A fuser device that fixes a toner image formed on a print sheet (medium) by heat and pressure is included in an electrographic printer (image forming apparatus) that transfers and fixes the toner image (developer image) of toner (developer) onto the print sheet.
As a conventional image forming apparatus, a fuser device (image heating device) described in JP Laid-Open Patent Application No. 2003-255755 performs duplex printing on a print sheet. However, when the duplex printing and fusion process are performed on the print sheet, conditions to heat during the fusion process on one surface and the other surface may need to be changed. For example, the fuser device described in JP Laid-Open Patent Application No. 2003-255755 performs a first fusion process and a second fusion process, in which the same medium is used, at respective different temperatures to solve disarrangement of an image due to a difference between gloss on a front surface and that on a back surface of the medium as well as re-melting of toner on the front surface during the duplex printing.
A fusion temperature on the front surface is lower than that on the back surface during performing the duplex printing. However, an image can hardly be obtained easily.
An object of the detailed examples disclosed in the present invention is to easily obtain an image.